我如何取一个Vec<Option<T>>
,其中T
不能被复制,然后打开所有Some
个值?
我在map
步中遇到了一个错误.我很高兴能转移原始名单的所有权,并"扔掉"None
.
#[derive(Debug)]
struct Uncopyable {
val: u64,
}
fn main() {
let num_opts: Vec<Option<Uncopyable>> = vec![
Some(Uncopyable { val: 1 }),
Some(Uncopyable { val: 2 }),
None,
Some(Uncopyable { val: 4 }),
];
let nums: Vec<Uncopyable> = num_opts
.iter()
.filter(|x| x.is_some())
.map(|&x| x.unwrap())
.collect();
println!("nums: {:?}", nums);
}
这就产生了错误
error[E0507]: cannot move out of borrowed content
--> src/main.rs:17:15
|
17 | .map(|&x| x.unwrap())
| ^-
| ||
| |hint: to prevent move, use `ref x` or `ref mut x`
| cannot move out of borrowed content